It is still James who makes the final decision, Acts 15:19
Now....visualize this.....here is the dynamic leader of a new movement exuding confidence, poise, leadership and devotion from his many followers. Galatians 2:12 Peter is afraid of the agents from James and the Jerusalem Church. In verse 4 Paul even identifies these people as false brothers who have infiltrated the ranks....and your "Papa" is helpless in his terror. Paul even has to kick his butt in front of everyone (verse 14).
If your "Papa" was the designated leader why are the "Twelve" in Luke 22:24 arguing about who is the greatest? And this, of course, happens much after the period of Matthew 16:18.
You win, brother. Congratulations